For a study, researchers sought to assess the association between income and life expectancy by race and ethnicity and changes in life expectancy in 2020 and 2021.

California fatalities from 2015 to 2021 were subjected to a retrospective ecological study to determine life expectancy at the state and census tract levels. The American Community Survey’s median household income (MHI) was used to categorize the tracts. The slope of the life expectancy-income gradient was then compared by year and by racial and ethnic makeup.

Between 2015 and 2021, there were 1,988,606 fatalities in California, including 654,887 between 2020 and 2021. The state’s life expectancy decreased from 81.40 years in 2019 to 79.20 years in 2020 and 78.37 years in 2021. About 7,962 out of 8,057 census tracts had MHI data available (98.8%; 1,899,065 fatalities). The mean MHI varied between the lowest and highest percentiles, from $21,279 to $232,261. From 0.075 (95% CI, 0.07-0.08) years per percentile in 2019 to 0.103 (95% CI, 0.098-0.108; P<.001) years per percentile in 2020 and 0.107 (95% CI, 0.102-0.112; P<.001) years per percentile in 2021, the slope of the relationship between life expectancy and MHI significantly increased. From 11.52 years in 2019 to 14.67 years in 2020 and 15.51 years in 2021, the difference in life expectancy between the richest and lowest percentiles has grown. Between 2019 and 2021, life expectancy decreased across Hispanic and non-Hispanic Asian, Black, and White people. It increased among non-Hispanic Asian populations by 3.04 years, non-Hispanic Black populations by 3.84 years, and non-Hispanic White populations by 1.90 years. Among Hispanic, Asian, Black, and White people, the income-life expectancy gradient increased significantly between 2019 and 2020 (0.038 [95% CI, 0.030-0.045; P<.001] years per percentile; 0.005-0.044; P=.02] years per percentile; 0.015 [95% CI, 0.010-0.020; P<.001] years per percentile; and 0.011 [95% CI, 0.007-0.015; P<.001] years per percentile among White individuals) and between 2019 and 2021 (0.033 [95% CI, 0.026-0.040; P<.001] years per percentile among Hispanic individuals; 0.024 [95% CI, 0.010-0.038; P=.002] years among Asian individuals; 0.024 [95% CI, 0.011-0.037; P=.003] years percentile among Black individuals; and 0.013 [95% CI, 0.008-0.018; P<.001] years percentile among White individuals). The gradient increased substantially more between Black and White populations in 2021 (P=.04) and Hispanic and White populations in 2020 (P<.001 in both years).

The retrospective analysis of income and mortality data at the census tract level for the years 2015 to 2021 in California showed a decline in life expectancy in both 2020 and 2021 as well as an increase in the life expectancy gap by income level compared to the pre-epidemic period that disproportionately impacted some racial and ethnic minority populations. Because of the study’s ecological design, it is difficult to draw conclusions about any particular person, and it was unclear whether the results applied outside of California.